Clear Messages Storage on Mac (Attachments & More)

Every photo, video, GIF, and sticker anyone has ever sent you in Messages is stored on your Mac — indefinitely, by default. That's why Messages often sits near the top of the storage list on a Mac that's synced iMessage for years. Here's how to find the biggest offenders and clear them without deleting your conversations.

Review the biggest attachments first

macOS has a built-in review tool that sorts Messages attachments by size, so start there — it finds in seconds what would take an evening of scrolling through chats:

1. Open System Settings → General → Storage.
2. Below the storage bar, click the ⓘ next to Messages.
3. Work through the tabs — Photos, Videos, GIFs and Stickers, and Top Conversations — each sorted with the largest items first.
4. Select anything you don't need and click Delete.

Deleting here removes the attachment files, not the surrounding conversation. Video is where the real space is: a handful of screen recordings and holiday clips often outweighs thousands of photos. You can select several items at once with shift-click before deleting, and the Top Conversations tab is worth a look too — a years-old group chat you've muted can quietly be the biggest single item in the list.

Clear attachments inside a conversation

To be more surgical, do it from Messages itself. Select a conversation and click the ⓘ button at the top right of the window. The details pane shows the conversation's photos and attachments; right-click any item and choose Delete to remove just that file while keeping the chat. Anything worth saving first can be dragged out to the Desktop, or right-clicked and added to your Photos library.

Deleting an entire conversation from the sidebar (right-click → Delete Conversation…) removes its messages and attachments in one go. It's the fastest way to reclaim space from a defunct group chat, but it's permanent — there's no undo, so export anything sentimental before you swing that hammer.

Cap your message history

Attachment cleanup treats the symptom; message retention treats the cause. If you never look back more than a year, tell Messages to stop keeping everything forever:

1. Open Messages, then Messages → Settings (⌘,) → General.
2. Set Keep messages to One Year or 30 Days.

Treat this switch with respect: the moment you confirm, everything older than the window is permanently deleted, and setting it back to Forever later stops future purges but does not restore anything. If your chat history matters, export or screenshot what you need before shortening it. While you're in the same General pane, note the Save received files to setting — files people send you land in that folder (Downloads by default), which is a second place Messages content quietly accumulates.

Messages in iCloud changes the math

With Messages → Settings → iMessage → Enable Messages in iCloud turned on, your history lives in iCloud and stays in sync across devices. That cuts both ways: delete a giant video on your Mac and it disappears from your iPhone too, freeing space everywhere — but there's no device-local copy to fall back on. The initial upload also counts against your iCloud storage plan, so a huge attachment history may need a plan upgrade before it fits. The files themselves live under ~/Library/Messages; don't prune that folder by hand, since the chat database indexes it and manual deletions can corrupt your history. Use the app or the Storage pane instead.

Keep an eye on the rest

Messages is usually just one line in a crowded storage bar. To see how it compares with Mail, Photos, and the ever-mysterious System Data, run through a full breakdown of what's taking up space on your Mac.